Converting Halogen Lights to Power LED Lights (Final Post)

This post documents a project of converting 100 Watt halogen lights to 3 x 10W power LED lights (Final Post). We have a total of 9 of these lights (900 Watts). For expected energy savings see the Results section at the end of this document.

This is also a good time to review the results of changes we have made over the past 6 months. Here is the total watts used per month comparing previous year to this year.

Month

Last Year

This Year

Watts Saved

Percent Saved

December

1099

774

325

29.6%

January

1213

755

458

37.8%

February

995

680

315

31.7%

March

1032

664

368

35.7%

Total

4339

2873

1466

33.8%

As you can see from the pictures below, the halogen lights can produce a lot of light in a very small space, in all directions. The light bulb itself is very small and the terminals are almost not visible, so they don’t block the light. It really is very hard to beat this light bulb in terms of performance.

100W Halogen light bulb

Light Fixture 1

Light Fixture 2

From the pictures of the light fixture, you can see that there isn’t a whole lot of space for the power LED lights and the heat sink to remove the heat from the LED lights and the DC power supply.

The smallest low profile heat sink I could find that would fit into the available space was an XBOX heat sink. I bought 5 of these by the pound from a local metal recycling store.

Heat Sink 1

Heat Sink 2

Pictures below show the heat sink after three 10W LED lights are installed. Instead of a single 30W LED light, I used three 10W power LED lights because this way the light is more diffused and it looks more like the original light. A single point light source would create more shades.

LED lights installed

When I ran some tests, it looked like passive cooling was not enough to remove all the heat generated by three LED lamps. I ordered a low profile 1 cm x 5 cm x 5 cm 12 DC Volt fans.

Low Profile Fans

Fan is installed to the back of the XBOX heat sink.

Fan Installed, Top View

Fan Installed, rear view

Although the fan is a 12V fan, I run it at 5 Volts to reduce the fan noise. 7805 regulator is connected across one of the LED lights which take about 9 Volts.

Finished LED lamp (with 7905)

Final Installation

Results

Unfortunately I did not have the Lux meter to measure the amount of light produced with the halogen light before I started the project. However, I can say that the three original halogen lights produced about 400 Lux when measured on the counter (using 300 Watts).

I measured the amount of light on the same spot as 320 Lux with the LED lights (using about 30 Watts). It is possible to increase the amount of light, but it really is hard to tell the difference between the original halogen lights and the LED lights.

The only problem is that you can hear the fans spinning when the bathroom is perfectly quiet. Maybe there is a way to use a nice looking passive heat sink, but I could not find such a solution. For the time being, for me this is an acceptable solution.

For the circuit diagram, please see the LED related earlier posts. Another thing to mention is that I had to remove the original socket to make more room for the LEDs.